Quantum Molecular Calculations Research Articles

Research on the molecular structure, solvent effects, quantum computing, topology, and biological aspects of 4-phenylcoumarin-7-yl-methacrylate as an anticancer agent

The objective of this research is to conduct both experimental and theoretical analyses on the synthesis and characterization of a new coumarin derivative known as 4-phenylcoumarin-7-yl-methacrylate (PCMA). To accomplish this, several methods including 1H-NMR, FT-IR, and UV-visible spectroscopy were employed, and atomic charges and bond parameters were calculated using the DFT-B3LYP/6-311G++(d,p) basis set. Additionally, topological properties such as Electron Localized Function, Localized Orbital Locator and Non-Covalent interactions (RDG-NCI) were thoroughly examined. The TD-DFT approach was used to calculate the UV-Vis absorption technique in various solvent media, and the Light Harvesting Efficiency was also investigated. An analysis of Frontier Molecular Orbitals (FMO), Molecular Electrostatic Potential (MEP), and Average Local Ionization Energy (ALIE) simulations were conducted to identify the optimal sites for both electrophilic and nucleophilic attacks. Nonlinear Optical (NLO) behavior was also examined by determining the dipole moment (μ), the linear polarizability (α), first hyperpolarizability (β) and second hyperpolarizability (γ) through the use of the same basis set. To better understand molecular stability and interactions, Natural Bond Orbital (NBO) analysis was performed, providing insights into hyperconjugative interactions, charge delocalization, and electron density (ED) among the molecular components. Electron-hole and TDM analysis were also conducted to investigate the various types of electron-excited states. This research will additionally explore the drug-likeness and docking potential of PCMA, with the goal of determining its suitability as a potential candidate for cancer treatment. This comprehensive study offers valuable insights into the structural, electronic, and biological properties of 4-phenylcoumarin-7-yl-methacrylate (PCMA).

Preface

The 48th Vietnam Conference on Theoretical Physics (VCTP-48) was held during 31 July - 3 August 2023 in Da Nang city, Viet Nam.The VCTP-48 was organized by the Institute of Physics, Vietnam Academy of Science and Technology (VAST) under the auspices of the Vietnamese Theoretical Physics Society (VTPS).The VCTP, formerly known as NCTP, has been an annual activity of VTPS since 1976. The VCTP is aimed to be an international conference for physicists in Vietnam, in the region and worldwide. Our mission is to foster scientific exchanges and to promote a high-standard level of research and education in Vietnam and in South East Asia.The conference covered a wide range of theoretical physics topics from 4 major fields:• Particle, nuclear and astrophysics,• Molecular physics, quantum optics and quantum computation,• Condensed matter physics,• Soft matter, biological and interdisciplinary physics.The conference was divided into 1 opening session, 9 oral sessions and 2 poster sessions. The duration of an invited talk is 40 minutes including time for discussion. The duration of an oral talk is 20 minutes including time for discussion.93 participants participated in the conference. 10 invited talks, 17 oral and 67 poster contributions were presented. The conference program and the abstract book can be found on the conference website: http://iop.vast.vn/vctp/48/.This volume contains 6 selected papers contributed by the participants.We gratefully acknowledge the financial support of the Unesco’s Category 2 International Centre of Physics (ICP) located at the Institute of Physics, VAST.Editors of the VCTP-48 ProceedingsTrinh Xuan Hoang, Tran Minh Tien, Hoang Anh Tuan, Vu Ngoc Tuoc, and Nguyen Huy VietList of Organizer, Sponsor, Chair, Organizing Committee, Program Committee, Secretariat and Participants are available in this pdf.

Process Parameter Optimisation for Endohedral Metallofullerene Synthesis via the Arc-Discharge Method

Fullerenes have a unique structure, capable of both encapsulating other molecules and reacting with those on the exterior surface. Fullerene derivatives have also been found to have enormous potential to address the challenges of the renewable energy sector and current environmental issues, such as in the production of n-type materials in bulk heterojunction solar cells, as antimicrobial agents, in photocatalytic water treatment processes, and in sensor technologies. Endohedral metallofullerenes, in particular, can possess unpaired electron spins, driven by the enclosed metal atom or cluster, which yield valuable magnetic properties. These properties have significant potential for applications in molecular magnets, spin probes, quantum computing, and devices such as quantum information processing,, atomic clocks, and molecular magnets. However, the intrinsically low yield of endohedral fullerenes remains a huge obstacle, impeding not only their industrial utilization but also the synthesis and characterization essential for exploring novel applications. The low yield and difficulty in separation of different types of endohedral fullerenes results in the usage of a large amount of solvents and energy, which is detrimental to the environment. In this paper, we analyse the methodologies proposed by various researchers and identify the critical synthesis parameters that play a role in increasing the yields of fullerenes.

Reformulation of All ONIOM-Type Molecular Fragmentation Approaches and Many-Body Theories Using Graph-Theory-Based Projection Operators: Applications to Dynamics, Molecular Potential Surfaces, Machine Learning, and Quantum Computing.

We present a graph-theory-based reformulation of all ONIOM-based molecular fragmentation methods. We discuss applications to (a) accurate post-Hartree-Fock AIMD that can be conducted at DFT cost for medium-sized systems, (b) hybrid DFT condensed-phase studies at the cost of pure density functionals, (c) reduced cost on-the-fly large basis gas-phase AIMD and condensed-phase studies, (d) post-Hartree-Fock-level potential surfaces at DFT cost to obtain quantum nuclear effects, and (e) novel transfer machine learning protocols derived from these measures. Additionally, in previous work, the unifying strategy discussed here has been used to construct new quantum computing algorithms. Thus, we conclude that this reformulation is robust and accurate.

Can Molecular Quantum Computing Bridge Quantum Biology and Cognitive Science?

Recently, quantum biology and molecular quantum computation have attracted substantial attention. Quantum biology applies quantum mechanics to biological systems at the molecular scale. Molecular quantum computing explores the degrees of freedom of molecules that can be used to produce quantum coherence, such as charge, orbital, opto-spin (interplay between optical excitation and spin), vibration, and rotation, to process quantum information. Cognitive science focuses on understanding how learning processes are realized, particularly within the human brain. The most common topic among these three is the computational process, which can exploit different levels of representation, either classical or quantum. Here, we review progress in quantum biology, molecular quantum computing, and quantum theory in cognitive science. Based on our critical analysis and review, we highlight that molecular quantum computing could be an important bridging research area between quantum biology and a deeper understanding of neuronal cells in cognitive science. Thus, these three areas can be the core to understanding how the classical world emerges from the quantum world and human intelligence. To answer these questions, we may gain insight by studying the quantum processes that underlie biological systems, such as photosynthesis and enzyme catalysis. An unprecedented opportunity for molecular quantum computing is to perform functionalities similar to those of the human brain. In this manner, we could not only expand the boundaries for quantum computing but also gain a better understanding of cognitive processes.

Electrical detection and modulation of magnetism in a Dy-based ferroelectric single-molecule magnet

Electrical control of magnetism in single-molecule magnets with peculiar quantum magnetic behaviours has promise for applications in molecular electronics and quantum computing. Nevertheless, such kind of magnetoelectric effects have not been achieved in such materials. Herein, we report the successful realization of significant magnetoelectric effects by introducing ferroelectricity into a dysprosium-based single-molecule magnet through spatial cooperation between flexible organic ligands and halide ions. The stair-shaped magnetization hysteresis loop, alternating current susceptibility, and magnetic relaxation can be directly modulated by applying a moderate electric field. Conversely, the electric polarization can be modulated by applying a small magnetic field. In addition, a resonant magnetodielectric effect is clearly observed, which enables detection of quantum tunnelling of magnetization by a simple electrical measurement. The integration of ferroelectricity into single-molecule magnets not only broadens the family of single-molecule magnets but also makes electrical detection and modulation of the quantum tunnelling of magnetization a reality.

Vibrational and Dipolar Calculations of Mg-(Li, Na, K) Polar Molecules

In this present paper, high-level ab-initio calculations were well performed using multi-configuration self-consistent field, multi-reference configuration interaction and pseudo-potentials methods of diatomic polar molecules compound to magnesium and an alkali atom (Li, Na, K) essentially for the ground and different low-lying excited electronic states of both symmetries 2,4Σ+ and 2,4Π. In this context, adiabatic potential energy curves have been carefully derived as well as the spectroscopic parameters for the different states correlated up to {Mg (3s2)+Li (4 s)}, {Mg (3s2)+Na (4p)} and {Mg (3s2)+K (4d)} asymptotic limits for the studied systems. The obtained results are discussed and compared with the previous theoretical and experimental works which feature in general a good agreement. Afterward, vibrational levels and their spacings as well as the permanent and transition dipole moment curves were accurately calculated. Finally, the turning points (intersection of the potential energy curve with the considered vibrational levels) as well as the ro-vibrational parameter (Bv), were determined for the ground (X)2Σ+ and the first excited state (2)2Σ+. Thanks to their strong dipole-dipole interaction as well as their long coherence time, some bibliographical review have affirmed that these molecular systems can be considered firstly as perfect potential carriers for information in the field of molecular quantum computing and secondly as very promising candidates for certain experiments such as photo-association and laser cooling.

Spin Catalysis in Photochemical Reactions and Its Applications to Quantum Information Nanotechnology

Chemistry as a science about spin and electric charge of micro particles which provide driving forces of atomic interactions and molecular structure transformations fits pretty well to the modern Quantum Information Science (QIS) requirements. Today’s computers operate only electric current signals in the semiconductor networks but the electron-spin properties are not exploited in a large extend. Spintronics provides spin-polarized currents and manipulates magnetic spin interactions; it uses mostly solid state chemistry of heavy elements. But a rich organic chemistry of solvents and fin films offers a great potential for molecular electronics and quantum computing. Photo-excited organic complexes of the “chromophore–radical” type provide good promise for many technological applications in molecular spintronics and electronics, including QIS technology. The doublet state photo excitation of stable organic radical being delocalized onto the linked anthracene molecule within picoseconds and subsequently evolved into a quartet state for big radicals (a pure high spin state) of the mixed radical-triplet character presents a sensible spin-optical interface for qubit in quantum computing. This high-spin state is coherently addressable with EPR microwaves even at room temperature, with the optical read-out induced by intersystem crossing (ISC) to emissive triplet state. Such integration of radical luminescence and high-spin states EPR provides the organic materials involvement into emerging QIS technologies

Preface

The 47th Vietnam Conference on Theoretical Physics (VCTP-47) was held during 1-4 August 2022 in Tuy Hoa city, Phu Yen province, Viet Nam.The VCTP-47 was organized by the Institute of Physics, Vietnam Academy of Science and Technology (VAST) under the auspices of the Vietnamese Theoretical Physics Society (VTPS).The VCTP, formerly known as NCTP, has been an annual activity of VTPS since 1976. The VCTP is aimed to be an international conference for physicists in Vietnam, in the region and worldwide. Our mission is to foster scientific exchanges and to promote a high-standard level of research and education in Vietnam and in South East Asia.The conference covered a wide range of theoretical physics topics from 4 major fields:• Particle, nuclear and astro-physics,• Molecular physics, quantum optics and quantum computation,• Condensed matter physics,• Soft matter, biological and interdisciplinary physics.The conference was divided into 1 opening session, 9 oral sessions and 2 poster sessions. The duration of an invited talk is 30-40 minutes including time for discussion. The duration of an oral talk is 20 minutes including time for discussion.The meeting was held onsite but all the sessions were broadcasted online on the Google Meet platform. There was only one fully online session with three invited speakers presenting their talks from abroad. For online viewing, the PDF files of the posters had be uploaded on to the conference website before the poster sessions.136 participants participated in the conference. 11 invited talks, 17 oral and 55 poster contributions were presented. The conference program and the abstract book can be found on the conference website: http://iop.vast.vn/vctp/47/.This volume contains selected papers contributed by the participants.We gratefully acknowledge the financial support of the Unesco’s Category 2 International Centre of Physics (ICP) located at the Institute of Physics, VAST.Editors of the VCTP-47 ProceedingsTrinh Xuan Hoang, Tran Minh Tien, Hoang Anh Tuan, and Vu Ngoc TuocList of Organizer, Sponsor, Chair, Organizing Committee, Program Committee, Secretariat, Participants are available in this Pdf.

Crystallite Tuning of Magnetic Properties in S = 1/2 Ni(III) Cyclam (Bi)sulfate Complex Salts

Molecular-level crystallographic tuning of a coordination complex structure can enable manipulation of the small energies that govern intra- and intermolecular responses toward molecular actuators. Chemically tuning of the magnetic response of S = 1/2 coordination complexes is of particular interest in recent years because these species represent the simplest electron-based quantum bits (qubits) for developing molecular quantum computers. In this report, we discuss the crystallographic tuning tools and corresponding magnetic properties of novel S = 1/2 Ni(III) cyclam complex salts: strong antiferromagnetic coupling in sulfate-bridged chain {[Ni(cyclam)(μ2-SO4)]ClO4·H2O}n (1) and field-, temperature-, and size-dependent slow magnetic relaxation in molecular [Ni(cyclam)(HSO4)2]HSO4 (2). We have reported two methods of manipulating the dynamic magnetic response of these coordination molecules: particle size selection and deuteration. We find that particle size dependency, which we attribute to the phonon bottleneck effect, for the magnetic dynamics in the parent compound 2, is removed in deuterated 2-d7, revealing only the faster molecular relaxation mode(s).

Triply-Reduced Hexa-peri-hexabenzocoronenes: Solid-State Structures and Magnetic Properties

Discotic polycyclic aromatics have attracted great interest in both fundamental chemistry and material science due to their degenerate frontier orbitals, high molecular symmetry, unique solid-state packing, and ability to bear a certain number of unpaired electrons that can be applied in molecular spintronics and quantum computing. In this work, chemical reduction of hexa-peri-hexabenzocoronenes, HBC (1) and tBu-HBC (2), as “superbenzenes”, has been investigated with K metal in THF solution. These reactions readily afforded the triply reduced HBC-based products which have been isolated as single-crystalline materials. The X-ray diffraction study confirmed the formation of π-complexes [K+(18-crown-6)(THF)2][{K+(18-crown-6)}2(13–)] (3) and [K+(18-crown-6)(THF)2][{K+(18-crown-6)}2(23–)] (4). In 3 and 4, two potassium ions were found to bind the central six-membered rings of 13– and 23– with one potassium counterion remaining solvent-separated from the complexes. A notable geometry distortion of the HBC core upon three-electron acquisition and metal binding was revealed in both complexes. The presence of bulky substituents in 2 affected the coordination and crystal packing of otherwise similar building units in 4 vs 3. The magnetic properties of 4 supported the existence of a well-isolated S = 3/2 ground state of the 23– triradical in the solid state.

Exciton delocalization in a fully synthetic DNA-templated bacteriochlorin dimer.

A bacteriochlorophyll a (Bchla) dimer is a basic functional unit in the LH1 and LH2 photosynthetic pigment-protein antenna complexes of purple bacteria, where an ordered, close arrangement of Bchla pigments-secured by noncovalent bonding to a protein template-enables exciton delocalization at room temperature. Stable and tunable synthetic analogs of this key photosynthetic subunit could lead to facile engineering of exciton-based systems such as in artificial photosynthesis, organic optoelectronics, and molecular quantum computing. Here, using a combination of synthesis and theory, we demonstrate that exciton delocalization can be achieved in a dimer of a synthetic bacteriochlorin (BC) featuring stability, high structural modularity, and spectral properties advantageous for exciton-based devices. The BC dimer was covalently templated by DNA, a stable and highly programmable scaffold. To achieve exciton delocalization in the absence of pigment-protein interactions critical for the Bchla dimer, we relied on the strong transition dipole moment in BC enabled by two auxochromes along the Qy transition, and omitting the central metal and isocyclic ring. The spectral properties of the synthetic "free" BC closely resembled those of Bchla in an organic solvent. Applying spectroscopic modeling, the exciton delocalization in the DNA-templated BC dimer was evaluated by extracting the excitonic hopping parameter, J to be 214 cm-1 (26.6 meV). For comparison, the same method applied to the natural protein-templated Bchla dimer yielded J of 286 cm-1 (35.5 meV). The smaller value of J in the BC dimer likely arose from the partial bacteriochlorin intercalation and the difference in medium effect between DNA and protein.

(Invited) N@C60 and N@C70 for Quantum Information Processing: Beyond Qubits

Endohedral fullerenes such as N@C60, where a single atomic nitrogen is trapped inside the fullerene cage, have been proposed as qubit architectures due to the remarkably long relaxation times of their p-electron spins (T1 = 0.375 ms, T2 = 0.25 ms). Molecular quantum computers are still at the fringes of the field as recent developments have focused on other implementations such as superconducting qubits. However, molecular approaches present some advantages such as the ability to use chemical functionalization for scaling up qubit architectures. This, combined with continuous progress on miniaturization of electrodes via e-beam lithography and other techniques, means that molecular approaches will continue to be of interest.In this talk, I will review the field of fullerene-based quantum information processing. I will present progress on the synthesis, chemical functionalization and alignment of N@C60 and N@C70 in different matrices. Recently, we were able to align N@C60 and N@C70 derivatives in a liquid crystal matrix with ordering parameter Ozz = 0.61. With the aligned samples, we were able to achieve addressability of the available 4-electron spin levels in endohedral nitrogen by coherent manipulations.Furthermore, these functionalized molecules give rise to endohedral fullerene qudits: multi-level computational units alternative to the conventional 2-level qubits. Qudits offer a larger state space for encoding information and thus can offer enhancement of quantum algorithm efficiency. Indeed, we were able to demonstrate the first ever geometric phase using pulsed EPR; something that was first proposed over 30 years ago!

Three-dimensional magneto-optical trapping model of CaH molecule based on multi-energy-level rate equation

Laser cooling and magneto-optical trapping of molecules is regarded as one of the state-of-the-art research fields in physics, which possesses broad applications in exploring fundamental physics beyond the Standard Model, quantum many-body physics, cold/ultracold chemistry and collision studies and so forth. Owing to the characteristic of highly diagonal Franck-Condon factors, lower saturation irradiance and larger scattering rate, the CaH molecule has been proposed as a promising candidate for laser cooling and magneto-optical trapping ever since 2004. Taking advantage of the multi-energy-level rate equation as well as the dual frequency effect, we evaluate the damping and trapping forces contained in the optical transitions of <inline-formula><tex-math id="M4">\begin{document}$ {\mathrm{A}}^{2}{\mathrm{Π}}_{1/2}\leftarrow {\mathrm{X}}^{2}{\mathrm{Σ }}^{+} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20220304_M4.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20220304_M4.png"/></alternatives></inline-formula> and <inline-formula><tex-math id="M5">\begin{document}${\mathrm{B}}^{2}{\mathrm{Σ }}^{+}\leftarrow {\mathrm{X}}^{2}{\mathrm{Σ }}^{+}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20220304_M5.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20220304_M5.png"/></alternatives></inline-formula>, analyze the cooling and trapping performance for different laser polarization sets, power values and detunings of four laser components, and determine the variations in the damping and trapping forces due to an additional frequency component. It is discovered that if the laser polarization is set to be <i>σ</i><sup>-</sup><i>σ</i><sup>+</sup><i>σ</i><sup>+</sup><i>σ</i><sup>+</sup><i>σ</i><sup>+</sup>, the detuning for the second laser component is <i>Γ</i><italic/> while the detuning of other components are set to be -2<i>Γ</i>, and the laser power is set to be 150 mW, one can obtain a damping acceleration of 28000 m/s<sup>2</sup>, and a trapping acceleration of 19000 m/s<sup>2</sup> for the transition of <inline-formula><tex-math id="M6">\begin{document}$ {\mathrm{A}}^{2}{\mathrm{Π}}_{1/2}\leftarrow {\mathrm{X}}^{2}{\mathrm{Σ }}^{+} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20220304_M6.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20220304_M6.png"/></alternatives></inline-formula>, both of which reach the optimal values under the current scope of the research and exhibit better performance than the CaF molecule. Our results, on one hand, not only offer an ideal method to comprehend the CaH MOT in theory but also help design the CaH MOT experiment or even achieve the Bose-Einstein condensation (BEC) of cold diatomic molecules. On the other hand, alkaline-earth-metal monohydrides (AEMHs) such as CaH, SrH and BaH are well-known for their permanent electric dipole moment, therefore these trapped diatomic molecules can be utilized to untangle the mechanism of dipole-dipole interaction, thus paving the way to realizing the molecular entanglement and quantum computing. More interestingly, current experimental systems for the non-zero measurement of the electron’s electric dipole moment (eEDM), including ThO, YbF and HfF<sup>+</sup>, still cannot be conducted simultaneously under the laser cooling and magneto-optical trapping technique while maintaining the ease of full polarization and internal co-magnetometry, all of which undoubtedly can increase the coherent measurement time and hence the statistical sensitivity, as well as the immunity to the systematic sensitivity. Previous studies reported that AEMHs share some similar characters with alkaline-earth-metal monofluorides (AEMFs) such as in electron correlation effects, however, the hyperfine energy level structures of AEMHs are relatively simpler than those of AEMFs, and AEMHs are prone to being polarized under the externally applied electric field. All of these lead to the trend that AEMHs may possess the dual character that it can be not only laser cooled and trapped in a MOT but also adopted as an candidate to measure the eEDM. Therefore, our work lays a substantial foundation for the theoretical and experimental study of SrH and BaH that inevitably will contribute to the exploration of the CP violation and new physics beyond the Standard Model on a scientific platform based on cold polar molecules, which is obviously different from large facilities such as the Large Hadron Collider.

Preface

The 45th Vietnam Conference on Theoretical Physics (VCTP-45) was held during 12-14 October 2020 in Vinh Yen city, Vinh Phuc province, Viet Nam.The VCTP-45 was organized by the Institute of Physics, Vietnam Academy of Science and Technology (VAST) under the auspices of the Vietnamese Theoretical Physics Society (VTPS).The VCTP, formerly known as NCTP, has been an annual activity of VTPS for 45 years. The VCTP is aimed to be an international conference for physicists in Vietnam, in the region and worldwide. Our mission is to foster scientific exchanges and to promote a high-standard level of research and education in Vietnam and in South East Asia.The conference covered a wide range of theoretical physics topics from 4 major fields:•Particle, nuclear and astro-physics,•Molecular physics, quantum optics and quantum computation,•Condensed matter physics,•Soft matter, biological and interdisciplinary physics.The conference was divided into one opening session, 10 oral sessions and 2 poster sessions separated by coffee and lunch breaks. The duration of an invited talk is 30 minutes including time for discussion. The duration of an oral talk is 20 minutes including time for discussion.Due to the Covid-19 pandemic, the conference was organized in a hybrid mode with both offline and online participation methods. The offline participation took place at the conference site, whereas the online participation was given over video conferencing. The Zoom and Microsoft Meeting softwares were used for the online participation and for broadcasting the offline sessions online. Poster presenters were requested to upload their posters on the conference website prior to the conference sessions. In general, both participation methods worked well except some limitations of the online method, such as for taking part in discussions. Due to international travel bans/restrictions, we did not have participants coming from abroad. There were, however, 3 participants who are from Japan and Philippines but working in Vietnam.150 participants participated in the conference including 98 offline and 52 online participants. 8 invited talks, 25 oral and 98 poster contributions were presented.This volume contains selected papers contributed by the participants.Editors of the VCTP-45 ProceedingsTrinh Xuan Hoang, Institute of Physics, VAST, hoang@iop.vast.ac.vn Hoang Anh Tuan, Institute of Physics, VAST, hatuan@iop.vast.ac.vn Vu Ngoc Tuoc, Hanoi University of Science and Technology, tuoc.vungoc@hust.edu.vn https://iop.vast.ac.vn/theor/conferences/nctp/45Organizer, logo, photos, List of Participants, Online participants, are available in the pdf

Nanooptomechanical Transduction in a Single Crystal with 100% Photoconversion.

Materials that exhibit nanooptomechanical transduction in their single-crystal form have prospective use in light-driven molecular machinery, nanotechnology, and quantum computing. Linkage photoisomerization is typically the source of such transduction in coordination complexes, although the isomers tend to undergo only partial photoconversion. We present a nanooptomechanical transducer, trans-[Ru(SO2)(NH3)4(3-bromopyridine)]tosylate2, whose S-bound η1-SO2 isomer fully converts into an O-bound η1-OSO photoisomer that is metastable while kept at 100 K. Its 100% photoconversion is confirmed structurally via photocrystallography, while single-crystal optical absorption and Raman spectroscopies reveal its metal-to-ligand charge-transfer and temperature-dependent characteristics. This perfect optical switching affords the material good prospects for nanooptomechanical transduction with single-photon control.

Symmetries and effect of time dimension in non-equilibrium quantum matter

Non-equilibrium quantum many-body systems have attracted considerable attention in the past decades. The scope of the research of this kind of novel system involves interdisciplinary research of condensed matter, atomic and molecular physics, quantum optics, quantum information and quantum computation, as well as the non-equilibrium statistical physics. The non-equilibrium phenomena emerging from the aforementioned quantum systems can exhibit rich and universal behaviors, which have far from being well understood due to the novelties and complexities of these systems, and hence the quantum many-body physics becomes the research highlight. At the same time, with the rapid development of quantum techniques, the understanding of these complex systems is of important practical significance due to their potential applications in quantum computation and quantum manipulation. In this paper, we show our recent progress of non-equilibrium quantum many-body systems. We focus on the novel phenomena closely related to the temporary symmetry breaking, including the exotic quantum matter, quasi-particles as well as the dynamical universality classes in non-equilibrium quantum many-body systems.

Manipulation of Molecular Spin State on Surfaces Studied by Scanning Tunneling Microscopy.

The adsorbed magnetic molecules with tunable spin states have drawn wide attention for their immense potential in the emerging fields of molecular spintronics and quantum computing. One of the key issues toward their application is the efficient controlling of their spin state. This review briefly summarizes the recent progress in the field of molecular spin state manipulation on surfaces. We focus on the molecular spins originated from the unpaired electrons of which the Kondo effect and spin excitation can be detected by scanning tunneling microscopy and spectroscopy (STM and STS). Studies of the molecular spin-carriers in three categories are overviewed, i.e., the ones solely composed of main group elements, the ones comprising 3d-metals, and the ones comprising 4f-metals. Several frequently used strategies for tuning molecular spin state are exemplified, including chemical reactions, reversible atomic/molecular chemisorption, and STM-tip manipulations. The summary of the successful case studies of molecular spin state manipulation may not only facilitate the fundamental understanding of molecular magnetism and spintronics but also inspire the design of the molecule-based spintronic devices and materials.

Largest molecular quantum computation performed

Researchers have used a quantum computer to model the electronic energy of diazene isomerization ( 2020, DOI: ). The scientists and other experts say the demonstration will be a building block for ...

VLSI for Next Generation CE

The current research in VLSI explores emerging trends and novel ideas and concepts covering a broad range of topics in the area of VLSI: from VLSI circuits, systems, and design methods, to system-level design and systemon- chip issues, to bringing VLSI methods to new areas and technologies such as nano and molecular devices, MEMS, and quantum computing. Future design methodologies are also key topics of Very Large Scale Integration (VLSI) research, as well as new Electronic Design Automation (EDA) tools to support them. The purpose of this special section is to provide an insight into current research and development in aspects related to ISVLSI.